Inductor for railway axle surface induction hardening

Abstract

The invention discloses an inductor for induction quenching of the surface of a railway axle. The inductor comprises the processes of inductor design, material selection, manufacturing, assembling and quenching. The main failure form of the axle is surface damage, such as fretting wear, bumping damage and corrosion. The surface of the axle is a key part for determining the safety and reliability of the axle. The surface induction quenching can improve the surface hardness and fatigue strength of the axle and prolong the service life. Railway axles are large in boundary dimension and have geometric discontinuity, and challenge is brought to implementation of induction quenching. The newly designed inductor solves the problems of unreasonable axle surface induction quenching heat shape, low heating efficiency, non-uniform quenching area heating and unreasonable stress distribution after induction quenching and tempering, prevents a step R corner hardening layer from being too shallow, and prevents the edge of the R corner from generating an overheated structure and quenching cracks; due to the fact that the newly-designed inductor is short in heating time, even in temperature and reasonable in heat type, stress distribution of products after induction quenching is more reasonable, fatigue strength of the axle is improved, and service life is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of induction hardening of rail transit axle surfaces, and in particular to an induction hardening sensor capable of continuously scanning and processing a plane and R-angle parts of a railway axle to achieve deep strengthening of the axle surface. Background Art

[0002] At present, my country's railway axles are made of carbon steel and alloy steel. The final heat treatment process for carbon steel axles is normalizing, and the final heat treatment process for alloy steel axles is quenching and tempering. The two types of axle products have low surface hardness and poor wear resistance, and are prone to fretting wear and fretting fatigue, threatening the service safety of the axles. Surface induction quenching can increase the surface hardness of the axle, improve the resistance to impact damage and fretting fatigue, and introduce a residual compressive stress layer with a thickness of 10 to 30 mm, which can inhibit the expansion of surface cracks, improve the fatigue strength of the axle, and extend the remaining life of the axle. At the same time, it helps to design the axle lightweight and improve the safety and economy of the axle throughout its life cycle.

[0003] Conventional automotive half-axle induction hardening treatment often uses fixed sensors. Sensors of different diameters are stacked in a stepped shape and wrapped around the shaft surface to complete the hardening of the target area of ​​the shaft surface at the same time. Some shaft parts use single-turn fixed-diameter arc sensors for rotary scanning hardening. The shape of the sensor and the heating position are as follows: Fig.13 As shown. Conventional sensors can basically meet the requirements of induction quenching of railway axle surfaces, but there are the following problems: First, the heating efficiency is too low, the heating time is too long, and the deformation and thermal shape cannot be effectively controlled; second, the thermal shape is poor, the heating layer depth is too deep at the step corners and the transition of the R corner edge, and the temperature is too high. The structure is coarse after induction quenching, and the surface tensile stress here is too large, and there is a risk of quenching cracks; third, the heating temperature at the center of the R corner is low, it is difficult to achieve martensitic transformation, the hardening layer depth is insufficient, the temperature difference with the R corner edge is large, the stress distribution is unreasonable, and the product service life is reduced; fourth, the fixed sensor has a complex structure, which is not conducive to the realization of fully automatic production in modern industrial production. Summary of the invention

[0004] In view of the technical problems raised above, the present invention provides a sensor for induction quenching of railway axle surfaces. The sensor provided by the present invention can shorten the induction quenching time of the axle surface, reduce the energy consumption of induction quenching of the axle surface, improve the induction quenching treatment efficiency of the axle surface, reduce the deformation of the axle after induction quenching, improve the qualified rate of the axle surface treatment, make the stress distribution after induction quenching uniform and reasonable, and improve the service life of the axle.

[0005] In order to solve the above technical problems, the specific technical solution of a sensor for induction hardening of a railway axle surface of the present invention is as follows:

[0006] An inductor for induction hardening of a railway axle surface, comprising a column, a cooling annular body, and a three-arc heating annular body;

[0007] The column is used to fix the cooling ring body and the three-arc heating ring body. The cooling ring body and the three-arc heating ring body are annular hollow structures. The plane formed by the circular arc of the ring body is parallel to the plane formed by the three arcs of the three-arc heating ring body. The column and the cooling ring body and the three-arc heating ring body respectively form a water passage, and form an electric passage with the three-arc heating ring body.

[0008] The water outlet holes are arranged in an array on the inner side of the cooling annular body;

[0009] The three-arc heating ring body is formed by connecting three arcs to form a ring, wherein the diameter of the first arc and the second arc are both D1, and the arc is 150°, the diameter of the third arc is D2, and the arc is 140°, one end of the first arc and the second arc are connected to the column water outlet, serving as the water inlet of the three-arc heating ring body; the third arc is provided with a water outlet, and the three arcs are all hollow structures, and are closed and connected for water flow;

[0010] The cross-sections of the first arc and the second arc are rectangular hollow structures, one side of the inner side of the ring is an arc-shaped protrusion, and the cross-section of the third arc is a rectangular hollow structure;

[0011] The surfaces of the first arc, the second arc and the third arc are provided with magnetic conductors, the cross-sections of the three magnetic conductors are all U-shaped, and the length of the magnetic conductors is less than or equal to the length of the arcs where they are located; the three magnetic conductors are stuck on the corresponding three sensor arcs from the outside of the ring to the inside of the ring by friction, and wrap the arcs where they are located;

[0012] The U-shaped ends of the first and second arcs are pointed, and the surface where the tip is located is in the same plane as one side of the inner side of the arc ring; the U-shaped ends of the third arc are flat, and the surface where the flat end is located is in the same plane as one side of the inner side of the arc ring.

[0013] The water flow cross-sectional area of ​​the three-arc heating annular body is 160-300 mm 2 .

[0014] The column includes two L-shaped structures, which are divided into a vertical surface and a bottom surface. The two vertical surfaces are fixed in parallel by bolts; the two bottom surfaces have water inlets, and the water outlet of the column is located at the upper ends of the two vertical surfaces; the interior of the column is closed and water flows.

[0015] The cooling annular body is composed of two identical semicircular arcs, and cooling water enters the cooling annular body through the water outlet at the upper end of the column, and multiple water outlets are evenly distributed on the cooling annular body.

[0016] The thickness of the arc wall contacted by the magnetic conductor is greater than or equal to 3 mm, and the thickness of the inner side walls of the three arcs are all 2 mm.

[0017] The railway axle is a multi-variable diameter cylinder with a radius transition at the variable diameter. During the induction quenching process, the XYZ three-axis servo motor CNC program of the quenching machine tool changes the position and controls the axial displacement speed, and the three arcs of the sensor are used to complete the induction quenching of different diameter shaft sections and radiuses of the train axle.

[0018] The first arc and the second arc are used for quenching the arc angle at the diameter change of the railway axle and the connected diameter sections; the third arc is used for quenching the long straight shaft section and other diameter sections of the axle.

[0019] The first arc of the sensor is used to process all upward rounded corners and their connected diameter segments, and the second arc of the sensor is used to process all downward rounded corners and their connected diameter segments.

[0020] The beneficial effects of the present invention are as follows:

[0021] The present invention provides an inductor for induction hardening of the surface of a railway axle, which has higher energy utilization and more reasonable heating energy distribution. Under the same power output conditions, the heating time at the R corner is shortened to about 50% of the original, and the heating time at the small diameter is shortened to 30% of the original, which greatly improves production efficiency; the newly designed inductor makes the axle deformation smaller, the thermal shape is uniform, and the hardening layer depth is evenly distributed, avoiding the risk of too deep or too shallow hardening layer and R corner edge quenching cracks. Because the temperature of the entire induction hardening area is uniform and the layer depth is consistent, the axle's anti-fretting wear ability and service life are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a typical geometric element diagram of a railway axle;

[0023] Figure 2 This is the three arc distribution diagram of the new sensor;

[0024] Figure 3 is a first arc cross-sectional view of the sensor;

[0025] Figure 4 is the second arc cross-sectional view of the sensor;

[0026] Figure 5 is the third arc cross-sectional view of the sensor;

[0027] Figure 6 is a cross-sectional view of a magnetic conductor;

[0028] Figure 7 Schematic diagram for processing upward rounded corners;

[0029] Figure 8 Schematic diagram of the processing of the middle long straight axis section;

[0030] Fig. 9 This is a schematic diagram of the downward rounded corner processing;

[0031] Fig.10 Process the top view for the large diameter Ф3;

[0032] Fig.11 Isometric cross-section diagram for heating the upward fillet R;

[0033] Fig.12 Isometric cross-section diagram for heating the downward fillet R;

[0034] Fig.13 This is a traditional sensor diagram;

[0035] Fig.14 A diagram of a sensor provided in accordance with an embodiment of the present invention. DETAILED DESCRIPTION

[0036] In order to better understand the purpose, structure and function of the present invention, the following is a further detailed description of an inductor for induction hardening of a railway axle surface of the present invention in conjunction with the accompanying drawings.

[0037] like Fig.14 As shown, an inductor for induction hardening of a railway axle surface of the present invention comprises a column, a cooling annular body, and a three-arc heating annular body;

[0038] The column is used to fix the cooling ring body and the three-arc heating ring body. The cooling ring body and the three-arc heating ring body are annular hollow structures. The plane formed by the arc of the cooling ring body is parallel to the plane formed by the three arcs of the three-arc heating ring body. The radius of the ring body is greater than or equal to the radius of any arc of the three-arc heating ring body. The column forms a water passage with the cooling ring body and the three-arc heating ring body respectively, and forms an electrical passage with the three-arc heating ring body.

[0039] like Figure 2 As shown, the three-arc heating ring body is formed by connecting three arcs to form a ring, wherein the diameter of the first arc and the second arc are both D1, and the arc is 150°, the diameter of the third arc is D2, and the arc is 140°, one end of the first arc and the second arc are connected to the column outlet, which serves as the water inlet of the three-arc heating ring body; the midpoint of the third arc is provided with a water outlet, and the three arcs are all hollow structures, and are closed and connected through water; the water cross-sectional area is 160-300mm 2 ; It can better cool the sensor and increase the service life of the sensor;

[0040] like Figure 3 As shown, the cross section of the first arc is a rectangular hollow structure, and one side located inside the ring is an arc-shaped protrusion; Figure 4 As shown, the cross section of the second arc is the same as the cross section of the first arc; Figure 5 As shown, the cross section of the third arc is a rectangular hollow structure.

[0041] like Figure 6 As shown, the surfaces of the first arc, the second arc, and the third arc of the inductor are respectively provided with magnets, and the cross-sectional shape of the magnets is all U-shaped, and the length of the magnets is less than or equal to the length of the arcs; the three segments of magnets are directly stuck on the corresponding three segments of the inductor arcs from the outer ring to the inner ring by friction in the form of wrapping, and this assembly method is conducive to disassembly and assembly and component maintenance. The U-shaped ends of the magnets of the first arc and the second arc are pointed, and the surface where the tip is located is on the same plane as one side of the inner side of the arc ring; the U-shaped ends of the magnets of the third arc are flat, and the surface where the flat end is located is on the same plane as one side of the inner side of the arc ring. Through the notch effect of the magnet, the current is driven to the position closest to the workpiece, and the wall thickness is increased to more than 3mm at this position (2mm at other positions). After thickening, the resistance of the current flowing through this position is smaller, which is more conducive to the passage of more current. At the same time, the total current density is reduced, the Joule heat of the inductor is reduced, and the energy utilization rate and the thermal fatigue life of the inductor are greatly improved.

[0042] like Figure 7 , 8 As shown in the top view in 9, the column includes two hollow L-shaped structures, which are divided into a vertical surface and a bottom surface, and the two vertical surfaces are fixed in parallel by bolts; the two bottom surfaces have water inlets, and the water outlet of the column is located at the upper ends of the two vertical surfaces; the column is closed and water flows inside. The first L-shaped structure connects the first arc, and the water flows through the closed connection; the second L-shaped structure connects the second arc, and the water flows through the closed connection. The cooling water enters the first arc and the second arc respectively through the water inlet at the lower end of the column, and after passing through the third arc, it flows out from the water outlet of the third arc, forming a closed passage connection as a whole.

[0043] Further, such as Fig.14 As shown, the cooling ring body is composed of two identical semicircular arcs and is a hollow structure. One end of the two semicircular arcs is respectively connected to the two L-shaped structures of the column. The cooling water enters the cooling ring body through the water outlet at the upper end of the column. The water outlet holes are arranged in an array on the inner side of the cooling ring body for water spray cooling. Multiple water outlets are evenly distributed on the ring body to form a water passage as a whole.

[0044] The sensor adopts the latest green laser 3D printing technology. The copper powder used for 3D printing uses oxygen-free copper TU1 with a larger RRR value. The effective circle part does not require brazing, which optimizes the sensor manufacturing process. It is made of Italian MagShape gray machinable magnetic conductive material.

[0045] like Figure 1As shown, it is a cross-sectional view of a railway axle along the center line of the cross section. The axle as a whole is a multi-diameter cylindrical shape, and the diameter change is transitioned by an arc; specifically, it includes 5 diameters, from the axle head, in order: small diameter Ф1, middle diameter Ф2, large diameter Ф3, rear middle diameter Ф4, large diameter Ф3, and the middle long straight shaft section Ф5 of the axle; the arc angle of the diameter change connection between the small diameter Ф1 and the middle diameter Ф2 is R1, the arc angle of the diameter change connection between the middle diameter Ф2 and the large diameter Ф3 is R2, the arc angle of the diameter change connection between the large diameter Ф3 and the rear middle diameter Ф4 is R3, and the arc angle of the diameter change connection between the large diameter Ф3 and the middle long straight shaft section Ф5 of the axle is R3.

[0046] Specifically, the first arc of the sensor is used to perform induction hardening on the small diameter Ф1, fillet R1, middle diameter Ф2, and fillet R2 of the railway axle; the third arc of the sensor is then used to perform induction hardening on the large diameter Ф3 of the axle, and then the sensor position is moved to perform induction hardening on the lower fillet R3 and diameter Ф4 using the second arc, and then the first arc and the third arc are used in sequence to perform induction hardening on the upper fillet R3 and large diameter Ф4, and the next long straight shaft section Ф5 is induction hardened using the third arc of the sensor, such as Figure 8 The second half of the implementation process is similar to the above, wherein the downward fillet R portion and the connected minor diameter Φ1, middle diameter Φ2, Φ4 are induction hardened using the second arc, as shown in FIG. Fig. 9 and Fig.12 The upward fillet R is heated using the first arc, as shown in FIG. Figure 7 and Fig.11 As shown. The third arc part of the large diameter Ф3 is used for heating treatment, as shown Fig.10 As shown. During the entire induction quenching process, the position of the sensor is changed and the axial displacement speed is controlled through the quenching machine XYZ three-axis servo motor CNC program; the magnetic conductor is used to drive the induced current to make it more concentrated, thereby improving the quenching efficiency; the first arc and the second arc are the water inlet end, and the third arc is the water outlet end, which can better cool the sensor and increase the life of the sensor.

[0047] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. An inductor for induction hardening of railway axle surface, characterized in that: It includes a column, a cooling ring body, and a three-arc heating ring body; The column is used to fix the cooling ring body and the three-arc heating ring body. The cooling ring body and the three-arc heating ring body are annular hollow structures. The plane formed by the circular arc of the ring body is parallel to the plane formed by the three arcs of the three-arc heating ring body. The column and the cooling ring body and the three-arc heating ring body respectively form a water passage, and form an electric passage with the three-arc heating ring body. The water outlet holes are arranged in an array on the inner side of the cooling annular body; The three-arc heating ring body is formed by connecting three arcs to form a ring, wherein the diameter of the first arc and the second arc are both D1, and the arc is 150°, the diameter of the third arc is D2, and the arc is 140°, and one end of the first arc and the second arc are connected to the column water outlet as the water inlet of the three-arc heating ring body; The third arc is provided with a water outlet, and the three arcs are all hollow structures, and are closed and connected with water; The cross-sections of the first arc and the second arc are rectangular hollow structures, one side of the inner side of the ring is an arc-shaped protrusion, and the cross-section of the third arc is a rectangular hollow structure; The surfaces of the first arc, the second arc and the third arc are provided with magnetic conductors, the cross-sections of the three magnetic conductors are all U-shaped, and the length of the magnetic conductors is less than or equal to the length of the arcs where they are located; the three magnetic conductors are stuck on the corresponding three sensor arcs from the outside of the ring to the inside of the ring by friction, and wrap the arcs where they are located; The U-shaped ends of the first and second arcs are pointed, and the surface where the tip is located is in the same plane as one side of the inner side of the arc ring; the U-shaped ends of the third arc are flat, and the surface where the flat end is located is in the same plane as one side of the inner side of the arc ring.

2. The inductor for induction hardening of a railway axle surface according to claim 1, characterized in that: The water flow cross-sectional area of ​​the three-arc heating annular body is 160-300 mm 2 .

3. The inductor for induction hardening of a railway axle surface according to claim 1, characterized in that: The column includes two L-shaped structures, which are divided into a vertical surface and a bottom surface. The two vertical surfaces are fixed in parallel by bolts; the two bottom surfaces have water inlets, and the water outlet of the column is located at the upper ends of the two vertical surfaces; the interior of the column is closed and water flows.

4. The inductor for induction hardening of a railway axle surface according to claim 1, characterized in that: The cooling annular body is composed of two identical semicircular arcs, and cooling water enters the cooling annular body through the water outlet at the upper end of the column, and multiple water outlets are evenly distributed on the cooling annular body.

5. The inductor for induction hardening of railway axle surface according to claim 1, characterized in that: The thickness of the arc wall contacted by the magnetic conductor is greater than or equal to 3 mm, and the thickness of the inner side walls of the three arc rings are all 2 mm.

6. The inductor for induction hardening of a railway axle surface according to claim 1, characterized in that: The sensor is prepared by 3D printing, and the three-arc heating ring is formed in one piece.

7. The inductor for induction hardening of a railway axle surface according to claim 1, characterized in that: The material of the magnetic conductor is Italian MagShape.

8. The inductor for induction hardening of railway axle surface according to claim 1, characterized in that: The railway axle is a multi-variable diameter cylinder with a radius transition at the variable diameter. During the induction quenching process, the XYZ three-axis servo motor CNC program of the quenching machine tool changes the position and controls the axial displacement speed, and the three arcs of the sensor are used to complete the induction quenching of different diameter shaft sections and radiuses of the train axle.

9. The inductor for induction hardening of a railway axle surface according to claim 8, characterized in that: The first arc and the second arc are used for quenching the arc angle at the diameter change of the railway axle and the connected diameter sections; the third arc is used for quenching the long straight shaft section and other diameter sections of the axle.

10. The inductor for induction hardening of a railway axle surface according to claim 9, characterized in that: The first arc of the sensor is used to process all upward rounded corners and their connected diameter segments, and the second arc of the sensor is used to process all downward rounded corners and their connected diameter segments.

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